caa a22 4500 386400288 CHVBK 20180307112156.0 cr unu---uuuuu 161130e198912 xx s 000 0 eng 10.1017/S0031182000059035 doi S0031182000059035 pii (NATIONALLICENCE)cambridge-10.1017/S0031182000059035 A comparison of fluorescein diacetate and propidium iodide staining and in vitro excystation for determining Giardia intestinalis cyst viability [Elektronische Daten] The viability of 4 human isolates of Giardia intestinalis cysts using either the fluorogenic vital dyes fluorescein diacetate (FDA) and propidium iodide (PI) or in vitro excystation was assessed. Whereas viable cysts, as defined by in vitro excystation were present in each of the 4 isolates, cysts from only 3 of the 4 isolates took up the vital dyes. FDA consistently over-estimated cyst viability whilst PI under-estimated non-viable cysts when compared with in vitro excystation. Following in vitro excystation, both FDA and PI stained a proportion of unexcysted cysts indicating that FDA stained cysts which were incapable of excystation, whereas PI did not stain all cysts which were incapable of excystation. One human cyst isolate, which underwent in vitro excystation, could not be stained with either FDA or PI. In the absence of currently more specific fluorescent indicators of viability, PI alone could be used to determine the lower limit of nonviability in positive water-related samples, where small numbers of cysts are to be expected. Copyright © Cambridge University Press 1989 Giardia intestinalis nationallicence cyst viability nationallicence excystation nationallicence staining nationallicence fluorogenic vital dyes nationallicence Smith A. L. Scottish Parasite Diagnostic Laboratory, Department of Bacteriology, Stobhill General Hospital, Glasgow G21 3UW Smith H. V. Scottish Parasite Diagnostic Laboratory, Department of Bacteriology, Stobhill General Hospital, Glasgow G21 3UW Parasitology Cambridge University Press 99/3(1989-12), 329-331 0031-1820 99:3<329 1989 99 PAR https://doi.org/10.1017/S0031182000059035 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0031182000059035 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Smith A. L. Scottish Parasite Diagnostic Laboratory, Department of Bacteriology, Stobhill General Hospital, Glasgow G21 3UW NATIONALLICENCE 700 1- Smith H. V. Scottish Parasite Diagnostic Laboratory, Department of Bacteriology, Stobhill General Hospital, Glasgow G21 3UW NATIONALLICENCE 773 0- Parasitology Cambridge University Press 99/3(1989-12), 329-331 0031-1820 99:3<329 1989 99 PAR CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge